Tag Archives: Prince William Sound

For humpback whale, so many fish, so little luck

This amazing photo of a humpback whale chasing a massive school of herring was taken in Prince William Sound by Rich Brenner of the Alaska Department of Fish and Game.

A lone humpback whale swims into a huge school of herring, which keeps moving away. Photos by Rich Brenner, Alaska Department of Fish and Game
A lone humpback whale swims into a huge school of herring, but the fish keep moving away.
Photo by Rich Brenner, Alaska Department of Fish and Game

Rich took the picture in April during an aerial survey of herring. He says he has observed many humpbacks feeding on herring during the spring survey, but this whale was not having much luck, probably because the water was so clear. As the whale approached, the herring kept moving away, creating odd patterns in the water.

“As I was watching the scene, I couldn’t help but think that the whale was expending a lot of energy and not receiving much in return,” Rich wrote me in an email. “But the shallow depth and clear water probably did not favor it.”

In the weeks prior to the flight, a large algae bloom covered this area near the village of Tatitlek. If the bloom had continued, the whale and much of the herring might have been difficult to see, he said.

“Thus, we were very pleased to get such a clear view of the situation and observe the movement of the herring along with the whale. The herring school undulated away from the whale, and they were able to keep a gap between them. Only once did we observe the whale lunging forward and getting under the school.”

The second photo, below, shows the whale lunging upward and possibly getting a mouthful of herring. The platform in the top photo is part of a frame for a net pen used to hold hatchery salmon before their release.

The spring herring survey measures the extent of the spawn along the shoreline, which is used to estimate the overall biomass in Prince William Sound.

Rich said he estimated that herring in this massive school would amount to several hundred tons. GIS experts will map the school to help construct a formal estimate of the biomass.

The state has not approved a commercial herring fishery in Prince William Sound since 1999. During the 1980s and early 90s, large numbers of herring were caught commercially, Rich said. Sometime around 1993, the population crashed and has never fully recovered.

“The reason for the depleted biomass, relative to the years when we had a commercial fishery, is a subject that has been hotly debated by scientists and others for the past 20 years,” he said.

As stated in an announcement by ADFG:

“Preliminary spawn estimates (from 2013) are 20.7 mile-days (south of Knowles Head) and 5.5 mile-days (north of Knowles Head), and 3.2 mile-days (Montague Island) for a total of 29.3 mile-days of spawn. This is fewer mile-days of spawn in PWS than in any year in which commercial fishing occurred since 1973.”

Another good source of information on herring is the Prince William Sound Science Center.

The humpback whale may have caught up with some of the fish, as it surges to the surface.
The humpback whale may have caught up with some of the herring, as it surges to the surface.